Real-time Updates

Live data delivery — WebSockets, Server-Sent Events, long polling, pub/sub systems, and the patterns that power chat, notifications, live dashboards, and collaborative editing.

Push Mechanisms

Master real-time push patterns — WebSockets, Server-Sent Events, long polling, and push notifications. Understand when and why to use each for live data delivery.

Long PollingWebSockets (Full-Duplex)Server-Sent Events (SSE)Push Notifications

Delivery Guarantees

Understand message delivery semantics — at-most-once, at-least-once, exactly-once, ordered delivery with offsets, and fan-out to subscribers. The reliability trade-offs behind every messaging system.

At-Most-Once / At-Least-Once / Exactly-OnceOrdered Delivery with OffsetsFan-out to Subscribers